/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright 2023 Red Hat
 */

#ifndef DATA_VIO_H
#define DATA_VIO_H

#include <linux/atomic.h>
#include <linux/bio.h>
#include <linux/list.h>

#include "permassert.h"

#include "indexer.h"

#include "block-map.h"
#include "completion.h"
#include "constants.h"
#include "dedupe.h"
#include "encodings.h"
#include "logical-zone.h"
#include "physical-zone.h"
#include "types.h"
#include "vdo.h"
#include "vio.h"
#include "wait-queue.h"

/* Codes for describing the last asynchronous operation performed on a vio. */
enum async_operation_number {
        MIN_VIO_ASYNC_OPERATION_NUMBER,
        VIO_ASYNC_OP_LAUNCH = MIN_VIO_ASYNC_OPERATION_NUMBER,
        VIO_ASYNC_OP_ACKNOWLEDGE_WRITE,
        VIO_ASYNC_OP_ACQUIRE_VDO_HASH_LOCK,
        VIO_ASYNC_OP_ATTEMPT_LOGICAL_BLOCK_LOCK,
        VIO_ASYNC_OP_LOCK_DUPLICATE_PBN,
        VIO_ASYNC_OP_CHECK_FOR_DUPLICATION,
        VIO_ASYNC_OP_CLEANUP,
        VIO_ASYNC_OP_COMPRESS_DATA_VIO,
        VIO_ASYNC_OP_FIND_BLOCK_MAP_SLOT,
        VIO_ASYNC_OP_GET_MAPPED_BLOCK_FOR_READ,
        VIO_ASYNC_OP_GET_MAPPED_BLOCK_FOR_WRITE,
        VIO_ASYNC_OP_HASH_DATA_VIO,
        VIO_ASYNC_OP_JOURNAL_REMAPPING,
        VIO_ASYNC_OP_ATTEMPT_PACKING,
        VIO_ASYNC_OP_PUT_MAPPED_BLOCK,
        VIO_ASYNC_OP_READ_DATA_VIO,
        VIO_ASYNC_OP_UPDATE_DEDUPE_INDEX,
        VIO_ASYNC_OP_UPDATE_REFERENCE_COUNTS,
        VIO_ASYNC_OP_VERIFY_DUPLICATION,
        VIO_ASYNC_OP_WRITE_DATA_VIO,
        MAX_VIO_ASYNC_OPERATION_NUMBER,
} __packed;

struct lbn_lock {
        logical_block_number_t lbn;
        bool locked;
        struct vdo_wait_queue waiters;
        struct logical_zone *zone;
};

/* A position in the arboreal block map at a specific level. */
struct block_map_tree_slot {
        page_number_t page_index;
        struct block_map_slot block_map_slot;
};

/* Fields for using the arboreal block map. */
struct tree_lock {
        /* The current height at which this data_vio is operating */
        height_t height;
        /* The block map tree for this LBN */
        root_count_t root_index;
        /* Whether we hold a page lock */
        bool locked;
        /* The key for the lock map */
        u64 key;
        /* The queue of waiters for the page this vio is allocating or loading */
        struct vdo_wait_queue waiters;
        /* The block map tree slots for this LBN */
        struct block_map_tree_slot tree_slots[VDO_BLOCK_MAP_TREE_HEIGHT + 1];
};

struct zoned_pbn {
        physical_block_number_t pbn;
        enum block_mapping_state state;
        struct physical_zone *zone;
};

/*
 * Where a data_vio is on the compression path; advance_data_vio_compression_stage()
 * depends on the order of this enum.
 */
enum data_vio_compression_stage {
        /* A data_vio which has not yet entered the compression path */
        DATA_VIO_PRE_COMPRESSOR,
        /* A data_vio which is in the compressor */
        DATA_VIO_COMPRESSING,
        /* A data_vio which is blocked in the packer */
        DATA_VIO_PACKING,
        /* A data_vio which is no longer on the compression path (and never will be) */
        DATA_VIO_POST_PACKER,
};

struct data_vio_compression_status {
        enum data_vio_compression_stage stage;
        bool may_not_compress;
};

struct compression_state {
        /*
         * The current compression status of this data_vio. This field contains a value which
         * consists of a data_vio_compression_stage and a flag indicating whether a request has
         * been made to cancel (or prevent) compression for this data_vio.
         *
         * This field should be accessed through the get_data_vio_compression_status() and
         * set_data_vio_compression_status() methods. It should not be accessed directly.
         */
        atomic_t status;

        /* The compressed size of this block */
        u16 size;

        /* The packer input or output bin slot which holds the enclosing data_vio */
        slot_number_t slot;

        /* The packer bin to which the enclosing data_vio has been assigned */
        struct packer_bin *bin;

        /* A link in the chain of data_vios which have been packed together */
        struct data_vio *next_in_batch;

        /* A vio which is blocked in the packer while holding a lock this vio needs. */
        struct data_vio *lock_holder;

        /*
         * The compressed block used to hold the compressed form of this block and that of any
         * other blocks for which this data_vio is the compressed write agent.
         */
        struct compressed_block *block;
};

/* Fields supporting allocation of data blocks. */
struct allocation {
        /* The physical zone in which to allocate a physical block */
        struct physical_zone *zone;

        /* The block allocated to this vio */
        physical_block_number_t pbn;

        /*
         * If non-NULL, the pooled PBN lock held on the allocated block. Must be a write lock until
         * the block has been written, after which it will become a read lock.
         */
        struct pbn_lock *lock;

        /* The type of write lock to obtain on the allocated block */
        enum pbn_lock_type write_lock_type;

        /* The zone which was the start of the current allocation cycle */
        zone_count_t first_allocation_zone;

        /* Whether this vio should wait for a clean slab */
        bool wait_for_clean_slab;
};

struct reference_updater {
        enum journal_operation operation;
        bool increment;
        struct zoned_pbn zpbn;
        struct pbn_lock *lock;
        struct vdo_waiter waiter;
};

/* A vio for processing user data requests. */
struct data_vio {
        /* The vdo_wait_queue entry structure */
        struct vdo_waiter waiter;

        /* The logical block of this request */
        struct lbn_lock logical;

        /* The state for traversing the block map tree */
        struct tree_lock tree_lock;

        /* The current partition address of this block */
        struct zoned_pbn mapped;

        /* The hash of this vio (if not zero) */
        struct uds_record_name record_name;

        /* Used for logging and debugging */
        enum async_operation_number last_async_operation;

        /* The operations to record in the recovery and slab journals */
        struct reference_updater increment_updater;
        struct reference_updater decrement_updater;

        u16 read : 1;
        u16 write : 1;
        u16 fua : 1;
        u16 is_zero : 1;
        u16 is_discard : 1;
        u16 is_partial : 1;
        u16 is_duplicate : 1;
        u16 first_reference_operation_complete : 1;
        u16 downgrade_allocation_lock : 1;

        struct allocation allocation;

        /*
         * Whether this vio has received an allocation. This field is examined from threads not in
         * the allocation zone.
         */
        bool allocation_succeeded;

        /* The new partition address of this block after the vio write completes */
        struct zoned_pbn new_mapped;

        /* The hash zone responsible for the name (NULL if is_zero_block) */
        struct hash_zone *hash_zone;

        /* The lock this vio holds or shares with other vios with the same data */
        struct hash_lock *hash_lock;

        /* All data_vios sharing a hash lock are kept in a list linking these list entries */
        struct list_head hash_lock_entry;

        /* The block number in the partition of the UDS deduplication advice */
        struct zoned_pbn duplicate;

        /*
         * The sequence number of the recovery journal block containing the increment entry for
         * this vio.
         */
        sequence_number_t recovery_sequence_number;

        /* The point in the recovery journal where this write last made an entry */
        struct journal_point recovery_journal_point;

        /* The list of vios in user initiated write requests */
        struct list_head write_entry;

        /* The generation number of the VDO that this vio belongs to */
        sequence_number_t flush_generation;

        /* The completion to use for fetching block map pages for this vio */
        struct vdo_page_completion page_completion;

        /* The user bio that initiated this VIO */
        struct bio *user_bio;

        /* partial block support */
        block_size_t offset;

        /*
         * The number of bytes to be discarded. For discards, this field will always be positive,
         * whereas for non-discards it will always be 0. Hence it can be used to determine whether
         * a data_vio is processing a discard, even after the user_bio has been acknowledged.
         */
        u32 remaining_discard;

        struct dedupe_context *dedupe_context;

        /* Fields beyond this point will not be reset when a pooled data_vio is reused. */

        struct vio vio;

        /* The completion for making reference count decrements */
        struct vdo_completion decrement_completion;

        /* All of the fields necessary for the compression path */
        struct compression_state compression;

        /* A block used as output during compression or uncompression */
        char *scratch_block;

        struct list_head pool_entry;
};

static inline struct data_vio *vio_as_data_vio(struct vio *vio)
{
        VDO_ASSERT_LOG_ONLY((vio->type == VIO_TYPE_DATA), "vio is a data_vio");
        return container_of(vio, struct data_vio, vio);
}

static inline struct data_vio *as_data_vio(struct vdo_completion *completion)
{
        return vio_as_data_vio(as_vio(completion));
}

static inline struct data_vio *vdo_waiter_as_data_vio(struct vdo_waiter *waiter)
{
        if (waiter == NULL)
                return NULL;

        return container_of(waiter, struct data_vio, waiter);
}

static inline struct data_vio *data_vio_from_reference_updater(struct reference_updater *updater)
{
        if (updater->increment)
                return container_of(updater, struct data_vio, increment_updater);

        return container_of(updater, struct data_vio, decrement_updater);
}

static inline bool data_vio_has_flush_generation_lock(struct data_vio *data_vio)
{
        return !list_empty(&data_vio->write_entry);
}

static inline struct vdo *vdo_from_data_vio(struct data_vio *data_vio)
{
        return data_vio->vio.completion.vdo;
}

static inline bool data_vio_has_allocation(struct data_vio *data_vio)
{
        return (data_vio->allocation.pbn != VDO_ZERO_BLOCK);
}

struct data_vio_compression_status __must_check
advance_data_vio_compression_stage(struct data_vio *data_vio);
struct data_vio_compression_status __must_check
get_data_vio_compression_status(struct data_vio *data_vio);
bool cancel_data_vio_compression(struct data_vio *data_vio);

struct data_vio_pool;

int make_data_vio_pool(struct vdo *vdo, data_vio_count_t pool_size,
                       data_vio_count_t discard_limit, struct data_vio_pool **pool_ptr);
void free_data_vio_pool(struct data_vio_pool *pool);
void vdo_launch_bio(struct data_vio_pool *pool, struct bio *bio);
void drain_data_vio_pool(struct data_vio_pool *pool, struct vdo_completion *completion);
void resume_data_vio_pool(struct data_vio_pool *pool, struct vdo_completion *completion);

void dump_data_vio_pool(struct data_vio_pool *pool, bool dump_vios);
data_vio_count_t get_data_vio_pool_active_requests(struct data_vio_pool *pool);
data_vio_count_t get_data_vio_pool_request_limit(struct data_vio_pool *pool);
data_vio_count_t get_data_vio_pool_maximum_requests(struct data_vio_pool *pool);

void complete_data_vio(struct vdo_completion *completion);
void handle_data_vio_error(struct vdo_completion *completion);

static inline void continue_data_vio(struct data_vio *data_vio)
{
        vdo_launch_completion(&data_vio->vio.completion);
}

/**
 * continue_data_vio_with_error() - Set an error code and then continue processing a data_vio.
 *
 * This will not mask older errors. This function can be called with a success code, but it is more
 * efficient to call continue_data_vio() if the caller knows the result was a success.
 */
static inline void continue_data_vio_with_error(struct data_vio *data_vio, int result)
{
        vdo_continue_completion(&data_vio->vio.completion, result);
}

const char * __must_check get_data_vio_operation_name(struct data_vio *data_vio);

static inline void assert_data_vio_in_hash_zone(struct data_vio *data_vio)
{
        thread_id_t expected = data_vio->hash_zone->thread_id;
        thread_id_t thread_id = vdo_get_callback_thread_id();
        /*
         * It's odd to use the LBN, but converting the record name to hex is a bit clunky for an
         * inline, and the LBN better than nothing as an identifier.
         */
        VDO_ASSERT_LOG_ONLY((expected == thread_id),
                            "data_vio for logical block %llu on thread %u, should be on hash zone thread %u",
                            (unsigned long long) data_vio->logical.lbn, thread_id, expected);
}

static inline void set_data_vio_hash_zone_callback(struct data_vio *data_vio,
                                                   vdo_action_fn callback)
{
        vdo_set_completion_callback(&data_vio->vio.completion, callback,
                                    data_vio->hash_zone->thread_id);
}

/**
 * launch_data_vio_hash_zone_callback() - Set a callback as a hash zone operation and invoke it
 *                                        immediately.
 */
static inline void launch_data_vio_hash_zone_callback(struct data_vio *data_vio,
                                                      vdo_action_fn callback)
{
        set_data_vio_hash_zone_callback(data_vio, callback);
        vdo_launch_completion(&data_vio->vio.completion);
}

static inline void assert_data_vio_in_logical_zone(struct data_vio *data_vio)
{
        thread_id_t expected = data_vio->logical.zone->thread_id;
        thread_id_t thread_id = vdo_get_callback_thread_id();

        VDO_ASSERT_LOG_ONLY((expected == thread_id),
                            "data_vio for logical block %llu on thread %u, should be on thread %u",
                            (unsigned long long) data_vio->logical.lbn, thread_id, expected);
}

static inline void set_data_vio_logical_callback(struct data_vio *data_vio,
                                                 vdo_action_fn callback)
{
        vdo_set_completion_callback(&data_vio->vio.completion, callback,
                                    data_vio->logical.zone->thread_id);
}

/**
 * launch_data_vio_logical_callback() - Set a callback as a logical block operation and invoke it
 *                                      immediately.
 */
static inline void launch_data_vio_logical_callback(struct data_vio *data_vio,
                                                    vdo_action_fn callback)
{
        set_data_vio_logical_callback(data_vio, callback);
        vdo_launch_completion(&data_vio->vio.completion);
}

static inline void assert_data_vio_in_allocated_zone(struct data_vio *data_vio)
{
        thread_id_t expected = data_vio->allocation.zone->thread_id;
        thread_id_t thread_id = vdo_get_callback_thread_id();

        VDO_ASSERT_LOG_ONLY((expected == thread_id),
                            "struct data_vio for allocated physical block %llu on thread %u, should be on thread %u",
                            (unsigned long long) data_vio->allocation.pbn, thread_id,
                            expected);
}

static inline void set_data_vio_allocated_zone_callback(struct data_vio *data_vio,
                                                        vdo_action_fn callback)
{
        vdo_set_completion_callback(&data_vio->vio.completion, callback,
                                    data_vio->allocation.zone->thread_id);
}

/**
 * launch_data_vio_allocated_zone_callback() - Set a callback as a physical block operation in a
 *                                             data_vio's allocated zone and queue the data_vio and
 *                                             invoke it immediately.
 */
static inline void launch_data_vio_allocated_zone_callback(struct data_vio *data_vio,
                                                           vdo_action_fn callback)
{
        set_data_vio_allocated_zone_callback(data_vio, callback);
        vdo_launch_completion(&data_vio->vio.completion);
}

static inline void assert_data_vio_in_duplicate_zone(struct data_vio *data_vio)
{
        thread_id_t expected = data_vio->duplicate.zone->thread_id;
        thread_id_t thread_id = vdo_get_callback_thread_id();

        VDO_ASSERT_LOG_ONLY((expected == thread_id),
                            "data_vio for duplicate physical block %llu on thread %u, should be on thread %u",
                            (unsigned long long) data_vio->duplicate.pbn, thread_id,
                            expected);
}

static inline void set_data_vio_duplicate_zone_callback(struct data_vio *data_vio,
                                                        vdo_action_fn callback)
{
        vdo_set_completion_callback(&data_vio->vio.completion, callback,
                                    data_vio->duplicate.zone->thread_id);
}

/**
 * launch_data_vio_duplicate_zone_callback() - Set a callback as a physical block operation in a
 *                                             data_vio's duplicate zone and queue the data_vio and
 *                                             invoke it immediately.
 */
static inline void launch_data_vio_duplicate_zone_callback(struct data_vio *data_vio,
                                                           vdo_action_fn callback)
{
        set_data_vio_duplicate_zone_callback(data_vio, callback);
        vdo_launch_completion(&data_vio->vio.completion);
}

static inline void assert_data_vio_in_mapped_zone(struct data_vio *data_vio)
{
        thread_id_t expected = data_vio->mapped.zone->thread_id;
        thread_id_t thread_id = vdo_get_callback_thread_id();

        VDO_ASSERT_LOG_ONLY((expected == thread_id),
                            "data_vio for mapped physical block %llu on thread %u, should be on thread %u",
                            (unsigned long long) data_vio->mapped.pbn, thread_id, expected);
}

static inline void set_data_vio_mapped_zone_callback(struct data_vio *data_vio,
                                                     vdo_action_fn callback)
{
        vdo_set_completion_callback(&data_vio->vio.completion, callback,
                                    data_vio->mapped.zone->thread_id);
}

static inline void assert_data_vio_in_new_mapped_zone(struct data_vio *data_vio)
{
        thread_id_t expected = data_vio->new_mapped.zone->thread_id;
        thread_id_t thread_id = vdo_get_callback_thread_id();

        VDO_ASSERT_LOG_ONLY((expected == thread_id),
                            "data_vio for new_mapped physical block %llu on thread %u, should be on thread %u",
                            (unsigned long long) data_vio->new_mapped.pbn, thread_id,
                            expected);
}

static inline void set_data_vio_new_mapped_zone_callback(struct data_vio *data_vio,
                                                         vdo_action_fn callback)
{
        vdo_set_completion_callback(&data_vio->vio.completion, callback,
                                    data_vio->new_mapped.zone->thread_id);
}

static inline void assert_data_vio_in_journal_zone(struct data_vio *data_vio)
{
        thread_id_t journal_thread = vdo_from_data_vio(data_vio)->thread_config.journal_thread;
        thread_id_t thread_id = vdo_get_callback_thread_id();

        VDO_ASSERT_LOG_ONLY((journal_thread == thread_id),
                            "data_vio for logical block %llu on thread %u, should be on journal thread %u",
                            (unsigned long long) data_vio->logical.lbn, thread_id,
                            journal_thread);
}

static inline void set_data_vio_journal_callback(struct data_vio *data_vio,
                                                 vdo_action_fn callback)
{
        thread_id_t journal_thread = vdo_from_data_vio(data_vio)->thread_config.journal_thread;

        vdo_set_completion_callback(&data_vio->vio.completion, callback, journal_thread);
}

/**
 * launch_data_vio_journal_callback() - Set a callback as a journal operation and invoke it
 *                                      immediately.
 */
static inline void launch_data_vio_journal_callback(struct data_vio *data_vio,
                                                    vdo_action_fn callback)
{
        set_data_vio_journal_callback(data_vio, callback);
        vdo_launch_completion(&data_vio->vio.completion);
}

static inline void assert_data_vio_in_packer_zone(struct data_vio *data_vio)
{
        thread_id_t packer_thread = vdo_from_data_vio(data_vio)->thread_config.packer_thread;
        thread_id_t thread_id = vdo_get_callback_thread_id();

        VDO_ASSERT_LOG_ONLY((packer_thread == thread_id),
                            "data_vio for logical block %llu on thread %u, should be on packer thread %u",
                            (unsigned long long) data_vio->logical.lbn, thread_id,
                            packer_thread);
}

static inline void set_data_vio_packer_callback(struct data_vio *data_vio,
                                                vdo_action_fn callback)
{
        thread_id_t packer_thread = vdo_from_data_vio(data_vio)->thread_config.packer_thread;

        vdo_set_completion_callback(&data_vio->vio.completion, callback, packer_thread);
}

/**
 * launch_data_vio_packer_callback() - Set a callback as a packer operation and invoke it
 *                                     immediately.
 */
static inline void launch_data_vio_packer_callback(struct data_vio *data_vio,
                                                   vdo_action_fn callback)
{
        set_data_vio_packer_callback(data_vio, callback);
        vdo_launch_completion(&data_vio->vio.completion);
}

static inline void assert_data_vio_on_cpu_thread(struct data_vio *data_vio)
{
        thread_id_t cpu_thread = vdo_from_data_vio(data_vio)->thread_config.cpu_thread;
        thread_id_t thread_id = vdo_get_callback_thread_id();

        VDO_ASSERT_LOG_ONLY((cpu_thread == thread_id),
                            "data_vio for logical block %llu on thread %u, should be on cpu thread %u",
                            (unsigned long long) data_vio->logical.lbn, thread_id,
                            cpu_thread);
}

static inline void set_data_vio_cpu_callback(struct data_vio *data_vio,
                                             vdo_action_fn callback)
{
        thread_id_t cpu_thread = vdo_from_data_vio(data_vio)->thread_config.cpu_thread;

        vdo_set_completion_callback(&data_vio->vio.completion, callback, cpu_thread);
}

/**
 * launch_data_vio_cpu_callback() - Set a callback to run on the CPU queues and invoke it
 *                                  immediately.
 */
static inline void launch_data_vio_cpu_callback(struct data_vio *data_vio,
                                                vdo_action_fn callback,
                                                enum vdo_completion_priority priority)
{
        set_data_vio_cpu_callback(data_vio, callback);
        vdo_launch_completion_with_priority(&data_vio->vio.completion, priority);
}

static inline void set_data_vio_bio_zone_callback(struct data_vio *data_vio,
                                                  vdo_action_fn callback)
{
        vdo_set_completion_callback(&data_vio->vio.completion, callback,
                                    get_vio_bio_zone_thread_id(&data_vio->vio));
}

/**
 * launch_data_vio_bio_zone_callback() - Set a callback as a bio zone operation and invoke it
 *                                       immediately.
 */
static inline void launch_data_vio_bio_zone_callback(struct data_vio *data_vio,
                                                     vdo_action_fn callback)
{
        set_data_vio_bio_zone_callback(data_vio, callback);
        vdo_launch_completion_with_priority(&data_vio->vio.completion,
                                            BIO_Q_DATA_PRIORITY);
}

/**
 * launch_data_vio_on_bio_ack_queue() - If the vdo uses a bio_ack queue, set a callback to run on
 *                                      it and invoke it immediately, otherwise, just run the
 *                                      callback on the current thread.
 */
static inline void launch_data_vio_on_bio_ack_queue(struct data_vio *data_vio,
                                                    vdo_action_fn callback)
{
        struct vdo_completion *completion = &data_vio->vio.completion;
        struct vdo *vdo = completion->vdo;

        if (!vdo_uses_bio_ack_queue(vdo)) {
                callback(completion);
                return;
        }

        vdo_set_completion_callback(completion, callback,
                                    vdo->thread_config.bio_ack_thread);
        vdo_launch_completion_with_priority(completion, BIO_ACK_Q_ACK_PRIORITY);
}

void data_vio_allocate_data_block(struct data_vio *data_vio,
                                  enum pbn_lock_type write_lock_type,
                                  vdo_action_fn callback, vdo_action_fn error_handler);

void release_data_vio_allocation_lock(struct data_vio *data_vio, bool reset);

int __must_check uncompress_data_vio(struct data_vio *data_vio,
                                     enum block_mapping_state mapping_state,
                                     char *buffer);

void update_metadata_for_data_vio_write(struct data_vio *data_vio,
                                        struct pbn_lock *lock);
void write_data_vio(struct data_vio *data_vio);
void launch_compress_data_vio(struct data_vio *data_vio);
void continue_data_vio_with_block_map_slot(struct vdo_completion *completion);

#endif /* DATA_VIO_H */